AN EYE FOR A CURIOSITY

THE CURRENT vogue for adopting the pursuits of the gentleman-scientist - a variant of young fogeyism - means that trophies from the history of science are attracting eager bidding. The in-thing among the new well- to-do is to install a Victorian telescope in the loft conversion, gen up on the correct use of an ivory-handled surgical saw, or don a tasselled smoking cap while showing well-dined guests a terrestrial globe that maps California as an island.

It is the same curatorial urge that led 18th-century European noblemen to assemble "cabinets of curiosities", whose proudly displayed contents ranged from meteorites to stuffed mermaids. Perhaps none is quite so bizarre, though, as a mid-19th-century cabinet, unearthed from a garage in the Midlands, containing some 2,000 glass eyes which is for sale at Sotheby's on Wednesday, estimated pounds 3,500-pounds 5,000.

Decorative antique globes led today's market until recently. Once bought only by the educated rich, they had become part of the furniture in aspiring middle-class homes by the 1870s. Proof that the scholarly "look", rather than genuine erudition, is once again driving prices, came when Sotheby's began whisking the antique globes out of its scientific instrument sales and putting them into its furniture sales. Two years ago, the auction house sold a pair of floor-standing library globes by the Victorian makers John and William Cary for pounds 63,250. Interior decorators were buying them for rich clients, outbidding the more scholarly collectors. And the market went mad.

Today, prices for big Cary globes have gone off the boil: a similar pair might fetch a mere pounds 40,000. But they are just about the only artefacts in the scientific and medical instrument market whose prices have slipped. The rest - dentists' tooth keys, Victorian microscopes, ornate ear trumpets, fancy stethoscopes, mahogany medicine chests, navigational sextants, even Victorian mortuary trolleys - are up about 40 per cent on the prices of five years ago, and their popularity is increasing. They are still underpriced.

Peter Delehar, dealer in "unusual scientific instruments" and organiser of today's 25th bi-annual International Antique Scientific and Medical Instru-ment Fair in London, is offering a 2ft high machine for perspective drawing on his stand. The machine dates back to 1830 and is by the French maker Adrien Garard. It has two eye-sights that move in unison with a pencil, to which they are connected by taut wire. It really works. Garard's wife used it to make exact drawings of the Palace of Versailles. The brass and steel contraption was shown at the Great Exhibition in London in 1851 and is priced at pounds 800. It is one to amaze the friends with.

Mr Delehar says: "Few people buy because they think these instruments will be worth more in, say, 10 years' time. They want instruments that are clever, ingenious - an intellectual challenge." He does not stock surgical instruments, though - too gruesome.

Medical instruments became popular earlier this decade when the wives of doctors, dentists and opticians began buying them as gifts for their husbands. Among the instruments rising most quickly in value are the antique ear trumpets and stethoscopes. Cylindrical wooden stethoscopes, beautifully turned by their French inventor Rene Laennec (1781-1826) could be had for pounds 6,000 a decade ago, but now sell for up to pounds 10,000. (Laennec's first stethoscope was a roll of paper - the idea was not only to amplify the patient's heartbeat but also to distance the physician from contagion.) A wooden "conversation aid" (ear trumpet) of the 1890s can still be bought at auction for less than pounds 200, but you might have to pay more than pounds 400 for a silver-plated one with a decorative scrolled grille. Ear trumpets and stethoscopes make ideal retirement presents - which may explain why so many retired people with medical and scientific skills have started collecting.

Many of the instruments at the fair - with 80 stands, Britain's foremost forum for medical and scientific collectors - will be from existing collections, but as prices rise, more and more tools and contraptions found in attics and garages are being offered for sale.

Curiosity and horror both confer value. Victorian ivory-handled tooth keys, for extractions, the source of much black humour at dentists' dinner parties, have risen to pounds 300 or so - about the same price as foetal skulls and 18th-century amputation saws. An 18th-century ebony-handled trepanning brace - for drilling holes in skulls - would cost pounds 400-pounds 600. Fearsome Victorian cervical forceps and dilators, for extracting babies - under pounds 200 at auction - are reminders of an era when the sympathetic female midwife often took second place to muscular male surgeons. The pathologist Rudolf Virchow summed up the male thinking of the Victorian "caring" professions: "Woman is a pair of ovaries with a human being attached, whereas man is a human being furnished with a pair of testes."

The biggest prices are for the magnificent astronomical instruments of the 16th century. In 1991, Christie's South Kensington got a record pounds 1,023,000, from a European collector, for two meticulously engraved gilt metal globes - one terrestrial, the other celestial - made in 1579 by the famous cartographer Gerardus Mercator for the Turkish Sultan Murad III. A third piece, an armillary sphere - a skeletal globe consisting of metal rings representing the movement of sun, moon, and planets - was missing. One year later, South Ken's scientific instruments specialist, Jeremy Collins, travelled to Europe, following up a telephone tip that a heap of "old brass rings engraved with numbers, letters and names" had turned up in a garage. It was the missing armillary sphere and last year it fetched pounds 771,500.

The eyes also turned up out of the blue after an elderly man invited Paul Burrows, a Solihull antiques dealer, to view some blue and white china. Mr Burrows was unimpressed, but bought it. Then the man asked: "Does this sort of thing interest you?", producing a little box containing 10 glass eyes. Mr Burrows nodded, whereupon the man shuffled among rubbish at the back of the garage and hauled out a rosewood glass-fronted cabinet containing 20 drawers. As Mr Burrows deals in furniture, the glass eyes were a bonus. They rattled, but he could not see them, because most of them had cupped into one another, jamming the drawers shut. He agreed a price on trust.

It took him six weeks, working two or three hours a day, to prise the drawers open. The eyes winked at him from the darkness as he gently prodded them with a piece of wire. He says: "I was stunned when I discovered there were so many."

The seller's great-grandfather had been a maker of artificial eyes for taxidermists. When the trade declined, he walked from his hometown, Gloucester, to Solihull, in search of work, ending up making artificial eyes for the medical profession.

The eyes are thin glass shells worn on the eyeballs like contact lenses. They moved as the eyeball moved, and were less unsightly than the spherical artificial eyes developed in the 1890s, which filled more of the socket. Each would have taken a day to make.

The cabinet contains eyes coloured from light blue through green and hazel to almost black with brownish whites; there are even eyes for infants. They are thought to be rejected mis-matches that became samples. A collector would keep them intact, in their cabinet, but they might also be bought by a jeweller to mount in rings and pendants.

As objects of contemplation, the eyes are probably less mind-expanding than the globes, armillary spheres or miniature, hand-cranked planetariums bought by the rich and powerful between the 16th and the 19th centuries, to remind themselves of their place in the cosmos. As aids to piety these were not conspicuously successful; historians may one day link the egocentric behaviour of European despots with the fact that early globes such as the Sultan Murad trio showed a geocentric universe - with the earth at the centre, in accordance with Ptolemy's system - not the sun. Religious controversy ensured that, despite Copernicus, geocentric globes continued to be made as late as the mid-18th century. Today, cosmology is once again a hot topic, and astronomical instruments that reveal the mental maps of our ancestors have become objects of fascination. It is the same fascination that made best-sellers of Longitude and Fermat's Last Theorem .

And the advent of home computing - not so difficult, after all - that has, according to Sotheby's Mark James, who has put together a sale of scientific books next month, helped to shift the frontiers of CP Snow's two cultures. Today, we are all scientists of a sort. The old-fashioned polymath is back.

Such are the aspirations that drive demand for objects as various as astrolabes and glass eyes. Instruments dating from the rise of the new science in the 17th century are particularly sought after because they are works of art made before there was any distinction between art and science. It was all "natural philosophy" in those days. The word "scientist" was not current until the early 19th century. So George III's collection of scientific instruments, preserved in the Science Museum in London, includes, for example, a silver microscope by George Adams with urn-topped plinths and entwined Greek lovers, harking back to the art of the classical world.

The decoration of astronomical instruments tailed off around the end of the 17th century and later, in the 1830s, Joseph Lister's research on antisepsis marked the end of decorative carved ivory handles on surgical instruments - they were recognised as providing hidey-holes for lethal germs. Only recently have post-Lister surgical instruments begun to rise in price.

For the aspiring polymath, next week's sale at Sotheby's offers, among the glass eyes and more than 50 globes, some affordable gentlemen's toys: a mid-19th-century table globe by Felkl of Prague, estimated at pounds 250-pounds 350; a 19th-century Phillips planisphere with a patent orrery for finding the position of planets at any hour during the year, pounds 300-pounds 400; a German 19th- century sighting telescope on a tripod with a manual altitude-azimuth, pounds 200-pounds 250; a mahogany medicine chest of about 1840, pounds 500-pounds 600; a host of sand-glass timers, some estimated at under pounds 500; and, modestly estimated at pounds 200-pounds 300, an early 19th-century brass sector, a ruler-like instrument for measuring anything from musical chords to cannon shot, signed by the renowned Nicholas Bion of Paris. Two books by Bion, in French, explaining how his instruments work, are estimated pounds 200-pounds 300 and pounds 400-pounds 600 in Mr James's book sale, which consists of the contents of a French collector's library. Buy the instrument, and the books.

Previous scientific and medical instrument sales have found buyers for the following decorative must- haves: a 19th-century lifesize veterinary anatomical model of a horse, with removable components (sold in January for pounds 29,900, well above the pounds 5,000-pounds 7,000 estimate); a 19th-century surgeon's mechanical chain saw (sold last year for pounds 23,000); and a late-17th-/early- 18th-century German ivory anatomical model of a pregnant women with removable parts (pounds 5,750 in 1996). All were sold at Christie's South Kensington.

International Antique Scientific and Medical Instrument Fair, today (10am-4pm), Radisson Portman Hotel, Portman Square, London W1, entry pounds 3 (0181 866 8659). Instruments of Science and Technology, Wednesday (10.30am), and Scientific Books, Tuesday, 3 November (10.30am), Sotheby's, 34-35 New Bond Street, London W1 (0171 293 5000). Scientific instrument sales also take place at Christie's South Kensington (0171 581 7611) and Bonhams (0171 393 3900)